Axial flow pump



y 1964 c. D. BOWER 3,132,595

4 Sheets-Sheet 1 HVVENTUR. CLARK 0. Bawsxe ATTOQA/E Y May 12, 1964 c. D. BOWER AXIAL FLOW PUMP 4 Sheets-Sheet 2 Filed Oct. 30. 1961 INVENTOR. CLARK Q Bow Ex? efiwm/ ATTORNEY 4 C. D. BOWER AXIAL FLOW PUMP May 12, 1964 4 Sheets-Sheet 5 Filed Oct. 30, 1961 m I an H e w. E a Z w 0 K w c. D. BOWER 3,132,595

AXIAL mow PUMP 4 Sheets-Sheet 4 BSMOADSEOH May 12, 1964 Filed Oct. '50, 1961 United States Patent 3,132,595 AXIAL FLOW PUMP Clark D. Bower, Whittier, Caiih, assignor to Layne &

Howler Pump Company, Los Angeles, Calif., a corporation of California Filed Oct. 30, 1961, Ser. No. 148,620 16 Claims. (Cl. 103 -87) This invention relates to a unitary device that comprises an axial flow pump and an inverted drive motor therefor.

An object of the present invention is to provide a combination pump and inverted motor such that each may be increased in length with the pump developing the desired headand the motor designed to develop the horsepower required to drive such a lengthened pump. Such lengthened units are ordinarily required to operate at a rotative speed greater than the first critical speed. Since, on acceleration through the first critical speed, vibration may be encountered in lengthened motor-pump units as contemplated, the inventionhas for another object to provide means to stabilize such vibration not only when the unit passes through its first critical speed but also at each succeeding critical speed as full rotative speed is obtained.

Another object of the invention is to provide, in such an assembly, hydraulic pressure balance on the motor to balance the pressure dilterential between the discharge and suction ends of the pump as imposed on the motor.

A still further object of the invention is to provide a combined unit, as above, in which the motor is submersible and is inverted. Thus, the outside of the motor rotates and the construction entails the use of anti-friction bearings that permit reverse rotation and reversal of thrust.

A yet further object of the invention is to provide a motor-pump unitary assembly of the character above referred to in which provision is made for circulating lubrication through and around the motor in copious quantities that assure continuous supply of lubricant to the bearings previously mentioned. p

Another object of the invention is to provide a unitary assembly as above in which the pump vanes are so mounted as to render multi-staging easy, thereby enabling proportioning the numbers of ditfusion and impeller vanes of t e pump, as desired. Thus, the hydraulic characteristics of the pump may be accurately controlled and/ or determined.

A still further object of the invention is to provide a combined motor and pump construction in which the pump design and characteristic may be varied by providing for interchangeability of the vane structure and arrangement. Therefore, based on the present combined device, the characteristics, number, size, proportion and disposition of the pump vanes, as well as providing singleor multistage design, may be had, as desired.

A further object. of the invention is to provide an axial flow pump embodying a particular relationship and control in the dimensions of the above-mentioned pump vane characteristics, whereby shut-off horsepower is lower than the horsepower at maximum etficiency and is also lower than the shut-oft power of conventional low-lift pumps of comparable head capacity at the same maximum efliciency.

A yet further object of the invention is to provide a motor-pump structure in which themotor is lubricated by pressure fluid and the same is isolated frornthe fluid passing through the pump.

A further object of the invention is to provide a structure, as above, in which, notwithstanding head and expansion of the fluid being pumped, the motor lubricant is maintained at a higher pressure than the pressure of the pump fluid, thereby insuring against ingress, for any reason whatever, of such pump fluid into the internal structure of the motor.

3,132,595 Patented May 12, 1964 This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description and which is based on the accompanying drawings. However, said drawings merely show, and the following description merely describes, preferred embodiments of the present invention, which are given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

FIG. 1 is a partly broken side elevational view, in quarter section, of an axial flow pump combined with an inte'riorly located operating motor according to the present invention.

FIG. 2 is a fragmentary sectional view of a modification. 7

FIG. 3 is a fragmentary crosssectional view as taken on the line 3-3 of FIG. 1.

FIG. 4 is an enlarged and detailed view showing a pressure-sealing feature of the invention.

FIG. 5, to the same scale, is a semi-schematic view of a form of pump vane arrangement, as used in the invention.

FIG. 6 is a longitudinal sectional view thereof.

FIG. 7 is a similarly enlarged and fragmentary sectional View of another form of pump vane arrangement.

FIG. 8 is a similar view of still another pump vane arrangement.

FIG. 9 is a quarter-sectioned elevational view of the discharge end of the present motor-pump unit and showing a modification.

FIG. 10 is a graph showing comparative performance curvesbetween aunit according to the present invention the axis of said caps and fixedly carried by the cap 12 and extending in a direction toward the bearing cap 11, a cap plate 14 rotationally carried by the cap 11, a vibranon-stabilizing bearing E5 in cap 11 for said cap plate 14, an anti-friction bearing 16 between said cap plate and the free end of the fixed axle 13, a second cap plate 17, opposed to the cap plate 14, rotationally carried by the fixed axle, an anti-friction bearing 18 between the axle and the cap plate 17, pressure-sealing means 19 between the latter cap plate and the cap 12 to balance against pressure between said cap plates 14 and 17, a tubular wall fit) that spans between said cap plates and defining an annular passage 21 between said wall and the housing 10, a stator 22 of a squirrel cage motor carried by the axle 13 in the interior space23 within said wall 20, a motor rotor 24 electrically associated with the stator 22 and carried on the inner face of the wall 20, a sealing plug 25 at one end of the axle and through which fluid to lubricate the bearings 16 and 18 is conducted to the interior space 23 and which sears around electrical conductors 26 to the motor stator to produce a potential therein that, by induction, energizes the rotor 24, means 27 to supply lubri eating fluid to space 23 at a pressure different and preferably greater than the pressure head on the pump, and

section 31, a pump section 32 connected by bolts to the inner end of section 31, an intermediate section 33 similarly connected to section 32, and an inlet end section 34 connected to the section 33. As can be seen in FIG. 1, the housing section 31 is integrally'connected to the end cap 11 by webs 35. Similar webs 36 integrally connect the section 33 with the end cap 12. It is common practice to provide sections 31 and 34 with flanges or other portions for connection of the housing in operative position.

The caps 11 and 12 are preferably conical, as shown, thereby providing the annulus 21 with enlarged inlet and discharge throats, as appear in FIG. 1, the same providing for a smooth and gradual change in flow velocity through passage 21.

In the preferred form of FIG. 1, the cap 11 is shown with an interior bearing boss 37 that defines a chamber 38 in the nose of the cap which is closed by an end plug 39. The larger inner, circular end of cap 11 is formed with an annular bearing face. Said chamber 38, by means i of a passage 38a in the bearing boss 37, has communication with an inner chamber 38b that is enclosed between the wall of cap 11 and the cap plate 14.

The cap 12, at its smaller outer end, has an axial bore 40 that is formed within an axial hub 41 that extends toward but short of the larger inner end of said cap. The inner space 42 defined by the cap 12 is open to the outside by means of holes 43.

The axle 13 is shown as a shaft that is fitted into bore 40, the same having a shoulder 44 that abuts the end of the hub 41 and is secured in place in the cap 12 by means of a nut 45. Said axle is formed with a bore 46 that is open at the inlet end of the structure. An annular shoulder 47 on said axle locates the bearing 16 on the discharge end of the axle, and a shoulder 48 on said axle locates the bearing 18, said shoulders 47 and 48 being opposed, as shown. A key 49 fixedly connects said axle and the cap 12.

The cap plate 14 is disposed inwardly of the cap 11 and has a hub 50 that is coaxial with the axle 13 beyond the free end thereof. The vibration-stabilizing bearing 15, shown as a sleeve-bushing bearing, is carried by the bearing boss 37 of the cap 11 and engages over said hub 50. It will be clear that said bearing 15 dampens or stabilizes any tendency of the cap plate 14 to vibrate on the axis thereof. Said cap plate 14 is formed with a peripheral or outer annular portion 51 that extends inward from the hub 50, the same having an intermediate portion 52 that houses the anti-friction bearing 16.

Said bearing 16 non-frictionally connects said axle 13 and the cap plate 14. The same is shown as a doublerace bearing with its inner race mounted on the axle and its outer race fitted, as above explained, in the portion 52 of the cap plate 14. Since said cap plate is steadied by the cap 11, due to bearing 15, the outboard end of the axle 13 is steadied by bearing 16 while the cap plate 14 is freely rotational around the axis of said axle.

The modification of FIG. 9 omits the bearing 15 between the cap 11 and the cap plate 14, but extends the axle, as at 130, to have bearing directly in the cap 11.

The cap plate 17 is disposed inward of the end cap 12 and has a central opening 53 through which the axle 13 extends. The outer peripheral portion 54 of said cap plate is fitted into the inner end of cap 12. The antifriction bearing 18 provides for a rotational fit of the plate 17 on the axle.

The pressure-sealing means 19, shown in detail in FIG. 4, comprises an expansion spring 55 that abuts the inner end of the cap hub 41, a follower ring 56 around the axle 13 and biased by said spring 55 inwardly toward the cap plate 17, an abutment ring 57 in said cap plate, and a pressure ring 58 interposed between the follower 56 and the ring 57 and transmitting the pressure of spring 55 to the plate 17 through the ring 57. As will later be clear, the internal pressure between cap plates 14 and 17 and within wall is greater, during operation, than is the outside pressure. Thus, the means 19 seals the chamber 42 from flow into chamber 23 so that pressure therein is effective against the cap plate 17, said pressure being the pressure at the inlet end of the flow through the pump.

The modification of FIG. 9 shows a similar pressuresealing means 19a, the same sealing chamber 38b so the pressure therein is effective against the cap plate 14 and is opposed to the pressure in chamber 42.

The tubular wall 20 spans between the peripheral portion 51 of the cap plate 14 and the peripheral portion 54 of the cap plate 17. Flange rings 59 Welded to Wall 20 and inward of the respective portions 51 and 54, are connected to said portions by cap screws 60, thereby fixedly connecting said wall 20 to the cap plates 14 and 17 to define the mentioned interior space 23. O-rings 61 seal between said wall 20 and the outer annular surfaces of the cap plates. Thus, the mentioned annular passage 21 separates the fixed outer housing 10 and the rotationallymounted assembly of cap plates 14 and 17 and cylindrical wall 20.

The motor stator 22 is generally typical of squirrel cage or similar induction motors and is here shown with a laminated-magnet stack 62 that is fixedly carried by the axle 13 with the usual induction windings 63. Said stack and windings are disposed between the cap plates 14 and 17.

The motor rotor 24 is shown with a laminated-magnet stack 64 affixed to the inside of wall 20 and having secondary windings 65, said rotor, in this case, being disposed between the flange rings 59 and, of course, electrically aligned with the stator 22.

The sealing plug 25 is shown as a non-metallic element thatis fitted tightly into the bore 46 of the axle. Since the bore 46 is open to the interior space 23 through a conductor-passing grommet 66 in the axle 13 and said axle is provided with one or more ports 67 in the vicinity of the bearing 18 so that lubrication fluid in space 23 may circulate freely around said bearing, said plug serves to effectively seal against ingress into the motor of fluid from the outside. It will be clear that the pressure-sealing means 19 also seals in said internal fluid against leakage to the space 42 which is open to outside fluid entry through holes 43.

The electrical conductors 26 pass longitudinally through said plug 25 to windings 63, the plug sealing around said conductors so that the latter may be brought to the motor while the latter is submersed in the medium in which the pump is operating.

The means 27 is provided because it is desirable that the fluid within the space 23 around the motor be a different fluid than the fluid circulating through the annular passage 21 and also have a higher pressure than the fluid being pumped, notwithstanding heat and expansion. To this end, the means 27 is shown as comprising an expansion chamber 68 that is external of the motor and is lo cated so as to be exposed or subject to the pressure of the fluid being pumped. Said chamber is disclosed as an elastic container 69 that is housed in a seat 70 provided in the section 34 of the housing 10. said seat is shown in a device for wet pit installation, and in FIG. 2, in a device for dry pit or pipe-line installation. The circumferential extent of the sausage-like container 69 may vary depending on the fluid capacity desired. Said expansion chamber is exposed to the fluid being pumped on its external surface and, interiorly, the same contains fluid 71 that is supplied to the space 23 around the motor and circulating around the bearings 16 and 18, around the former because of passage 72 in the axle 13 and passage 73 in the cap plate 14, and around the latter because of the mentioned ports 67 in the axle and passage 74 in the cap plate 17.

Said means 27 provides for placing pressure on the fluid 71. To this end, a band 75, placed in tension by a spring or comparable means 76, compresses the outside of the container 69. The bias of spring 76 may be set In FIG. 1,

as desired and in relation to the pressure at the inlet end of the. pump, irrespective of the type .of installation used. A tube 77 extends from the container 69 and connects to a tubular fitting 78 that extends through sealing element 25 and discharges into thebore 46 of the axle from which fluid from container 69 enters space 23 through the grommet 66 and the ports 67.

It will be noted that the means 27 is integrated with the present pump-motor tmit so that facility of handling and connection of the parts is had.

By conducting inlet pressure of the pump, by means of a pipe 79, to chamber 38b by way of chamber 38 and passage 38a of FIG. 1, or directly to chamber 38b of FIG. 9, the opposite ends of the rotor,'i.e., the cap plates 14 and 17, are subject to the substantially equal and opposite pressure of chambers 38b and 42.

Three different forms of pump means 28 are shown. In the form shown in FIGS. 1, 5 and 6, said means comprises a propeller 80 carried by the motor rotor and comprising a set of vanes 81 extending radially outward from a ring or rings 82 that are adaped to be longitudinally stacked on the rotor wall 2th and held-in place by cap screws 83 that connect a thickened annular portion 34 of one of said rings 82 to the outer portion 51 of the cap plate 14. A sealing ring 85 seals against difierential hydraulic pressure between the discharge end of the pump and the motor. between the large end of the cap 11 and the portion 84 of the end impeller ring 82.

The number, dimensions, proportions and placement of the stationary vanes 36 that cooperate with the rotating vanes 81 and which extend radially inward from a fixed sleeve 8'7 fitted in pump section 32 of the housing provide characteristics that are advantageous and produce efiicient pumping operation. i

The vanes 86 are disposed on the discharge side of the vanes 81 and receive the discharge of the latter vanes on their concave faces for expression in an outward direction toward the left, as in'FIGS. 1, 5 and 6.

Where A=Width of stationary vanes B=Vane spacing B C=Length of stage D =Hub diameter D =Vane outer diameter P=Pitch in inches -OA to 1.0 %=0.25 to 0.5

The foregoing, while exemplary, is preferred, as is a propeller pitch ratio of 8 to 22 for a iii-inch axial flow pump. Also, the ratio of P -.89 to 2.45

is preferred.

Referring to the chart, FIG. 10, an axial flow turbine which has the number, dimensions, and placement of the vanes as above set forth and for a capacity of 1500 gallons per minute as shown at point 95, will operate at peak or maximum horsepower of about ten, as indicated at point 96. It will be noted from the horsepower line 97 that the brake horsepower lowers as flow decreases, dropping to nine horsepower at zero discharge or shut-off as indicatedat 98. When this performance is compared to the performance of a conventional low-lift pump of the same flow capacity at the same maximum horsepower, the horsepower at shut-off rises to sixty, as indicated at 99. Pump life, uniformity of performance, and a general improvement in operating efficiency, follow from In this case, said ring is interposed such design and arrangement changes over conventional low-lift pumps.

The present pump may be designed as a singleor multi-stage centrifugal type pump, as in FIG. 7, the pump stator 32a replacing the housing section 32 and mounting oneor more stationary bowl units 88, and the pump rotor a being provided with one or more cooperating impellers 89. The latter produce a centrifugal force on the fluid being pumped and are expressed in a discharge direction by the stationary units 88.

A mixed flow may be provided, as in FIG. 8, wherein the housing section 32 mounts a fixed bowl 90, a spacer 91, if needed, fixing said bowl in place, and the rotor 80b being provided with a cooperating impeller 92. The mixed flow is caused by designing said bowl and impeller to give both longitudinal and centrifugal forceto the fluid being moved by the pump.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the constructions are, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular forms of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

l. A pump comprising a fixed tubular housing, two hollow, longitudinally spaced end caps within and rigidly connected to said housing, oneat the inlet and the other at the outlet end of the pump, affixed axle extending from one cap toward the other, an induction motor stator fixedly carried by said axle between said caps, a tubular wall coaxial with said axle and disposed between said caps, a pair of cap plates on opposite sides of the stator closing the ends of said tubular wall and respectively closing the hollows of the caps, a rotational bearing between one cap and the cap plate at that end, an antiand the other by the fixed tubular pump housing, the hollows of both caps being vented to the inlet end of the pump to provide equal and opposite pressure in said hollows against the cap closure plates to balance the pressure differential between the discharge and suction ends of the pump as imposed on the motor rotor.

2. A pump according to claim 1 in which the axle is provided with an extension beyond the first-mentioned anti-friction bearing, and a bearing for said extension is provided in the first-mentioned cap.

3. A pump comprising a fixed tubular housing, two hollow, longitudinally spaced end caps within and rigidly connected to said housing, one at the inlet and the other at the outlet end of the pump, a fixed axle extending from one cap toward the other, an induction motor stator fixedly carried by said axle between said caps, a tubular wall coaxial with said axle and disposed between said caps, a pair of cap plates on opposite sides of the stator closing the ends of said tubular wall and respectively closing the hollows of the caps, a rotational hearing between one cap and the cap plate at that end, an anti-friction bearing between the latter cap plate and the axle, an anti-friction bearing between the other cap plate and the axle, means rigidly connecting said tubular wall and the the mentioned stator, the hollows of both caps being vented to the inlet end of the pump to provide equal and opposite pressure in said hollows against the cap closure plates to balance the pressure differential between the discharge and suction ends of the pump as imposed on the motor rotor means to conduct lubrication fluid into said interior space, means to place said fluid under pressure, a shoulder on said axle, means to resiliently bias the stator-enclosing assembly against said shoulder, an annular passage being defined between the tubular housing and the tubular wall, and cooperating pump components disposed in said passage, one carried by the rotational tubular wall and the other by the fixed tubular pump housing.

4. A pump according to claim 3 in which the axle is provided with an extension beyond the first-mentioned anti-friction bearing, and a bearing for said extension is provided in the first-mentioned cap.

5. A pump comprising a fixed tubular housing, two hollow, longitudinally spaced end caps within and rigidly connected to said housing, one at the inlet and the other at the outlet end of the pump, a fixed axle extending from one cap toward the other, an induction motor stator fixedly carried by said axle between said caps, a tubular wall coaxial with said axle and disposed between said caps, a pair of cap plates on opposite sides of the stator closing the ends of said tubular wall and respectively closing the hollows of the caps, a rotational bearing between one cap and the cap plate at that end, an anti-friction bearing between the latter cap plate and the axle, an anti-friction bearing between the other cap plate and the axle, means rigidly connecting said tubular wall and the cap plates to form a stator-enclosing assembly rotational on the axle and having an interior space, a motor rotor carried by said tubular wall in electrical relationship to the mentioned stator, the hollows of both caps being vented to the inlet end of the pump to provide equal and opposite pressure in said hollows against the cap closure plates to balance the pressure differential between the discharge and suction ends of the pump as imposed on the motor rotor means to conduct lubrication fluid into said interior space, means to place said fluid under pressure, a shoulder on said axle, means to resiliently bias the stator-enclosing assembly against said shoulder, passage and port means in said axle to conduct said lubrication to said interior space and around the anti-friction hearings to lubricate the latter, an annular passage being defined between the tubular housing and the tubular wall, and cooperating pump components disposed in said passage, one carried by the rotational tubular wall and the other by the fixed tubular pump housing.

6. A pump comprising a fixed tubular housing, two hollow, longitudinally spaced end caps within and rigidly connected to said housing, one at the inlet and the other at the outlet end of the pump, a fixed axle extending from one cap toward the other, an induction motor stator fixedly carried by said axle between said caps, a tubular wall coaxial with said axle and disposed between said caps, a pair of cap plates on opposite sides of the stator closing the ends of said tubular wall and respectively closing the hollows of the caps, a rotational bearing between one cap and the cap plate at that end, an anti-friction bearing between the latter cap plate and the axle, an anti-friction bearing between the other cap plate and the axle, means rigidly connecting said tubular wall and the cap plates to form a stator-enclosing assembly rotational on the axle and having an interior space, a motor rotor carried by said tubular wall in electrical relationship to the mentioned stator, the hollows of both caps being vented to the inlet end of the pump to provide equal and opposite pressure in said hollows against the cap closure plates to balance the pressure difierential between the discharge and suction ends of the pump as imposed on the motor rotor, said axle having an end bore with ports and passages extending from said bore into said interior space, a compressible plug closing said bore, means extending through said plug to conduct fluid under pressure through said bore, ports and passages, an annular passage being defined between the tubular housing and the tubular wall, and cooperating pump components disposed in said passage, one carried by the rotational tubular wall and the other by the fixed tubular pump housing.

7. A pump according to claim 6 provided with electrical coductors to supply current to the stator, said conductors extending longitudinally through said plug and tightly sealed therein.

8. In a pump, a fixed tubular housing, a multi-stage pump component fixedly carried within the housing, a pair of oppositely arranged coaxial and hollow caps within said housing, one at the inlet and the other at the outlet end of the pump, with an annular passage therebetween, a fixed axle carried by one cap and extending coaxially toward the other cap, a motor stator between the caps and fixed on the axle, an enclosed motor housing rotationally mounted on the axle and enclosing the motor stator, said motor housing having an outer tubular wall, a motor rotor carried by said wall in electrical association with the stator and provided with end plates in hollow-enclosing engagement with the hollow caps, the hollows of said caps being vented to the inlet of the pump to hydraulically balance the thrust, on opposite ends, on the motor housing, and a second multi-stage pump component carried by said wall and operatively associated with the mentioned multi-stage fixed component, the length of the tubular wall and of the motor being proportional to the length of the operatively associated pump components.

9. In a pump according to claim 8, means to supply lubrication fluid to said motor housing, and means mounted on the fixed housing to place said fluid under pressure greater than the suction pressure of the fluid being pumped between the pump components.

10. In a pump according to claim 8, said axle having fluid passages therein to conduct said fluid to the motor housing, a plug closing the end of said axle passages, and a connection between the means to place the fluid under pressure and extending longitudinally through said plug into communication therebeyond with the mentioned fluid passages.

11. In a pump, a fixed tubular housing, a pump component fixedly carried within the housing, a pair of oppositely arranged coaxial and hollow caps within said housing, one at the inlet and the other at the outlet end of the pump, with an annular passage therebetween, a fixed axle extending between and having its ends in bearing engagement with said caps, a motor stator between the caps and fixed on the axle, an enclosed motor housing rotationally mounted on the axle and enclosing the motor stator, said motor housing having an outer tubular wall, a motor rotor carried by said wall in electrical association with the stator and provided with end plates in hollow-enclosing engagement with the hollow caps, the hollows of said caps being vented to the inlet of the pump to hydraulically balance the thrust, on opposite ends, on the motor housing, and a second pump component carried by said wall and operatively associated with the mentioned fixed component.

12. In a pump, a fixed tubular housing, a pump component fixedly carried within the housing, a pair of oppositely arranged coaxial and hollow caps within said housing, one at the inlet and the other at the outlet end of the pump, with an annular passage therebetween, a fixed axle carried by one cap and extending coaxially toward the other, a motor stator between the caps and fixed on the axle, an enclosed motor housing rotationally mounted on the axle and enclosing the motor stator, said motor housing having an outer tubular wall, a motor rotor carried by said wall in electrical association with the stator and provided with end plates in hollow-enclosing engagement with the hollow caps, the hollows of said caps being vented to the inlet of the pump to hydraulically balance the thrust, on opposite ends, on the motor housing, and a second pump component carried by said wall and operatively associated by the mentioned fixed component, the fixed pump component comprising an annular sleeve having an internal diameter D and provided with radial and inwardly directed vanes on circumferential spacing B and having a width A, the rotational pump component comprising a ring having an ex ternal diameter D and a length C, said diameters, vane spacing, vane Width and ring length being proportionally related substantially as follows:

said proportionally related internal and external diameters, circumferential spacing, vane width, and ring length providing a pump having a shut-oil brake horsepower lower than the peak horsepower of the pump.

13. In pump, a fixed tubular housing, a pump component fixedly carried within the housing, a pair of oppositely arranged coaxial and hollow caps within said housing, one at the inlet and the other at the outlet end of the pump, with an annular passage therebetween, a fixed axle carried by one cap and extending coaxially to ward the other, a motor stator between the caps and fixed on the axle, an enclosed motor housing rotationally mounted on the axle and enclosing the motor stator, said motor housing having an outer tubular wall, a motor rotor carried by said wall in electrical association with the stator and provided with end plates in hollow-enclosing engagement with the hollow caps, the hollows of said caps being vented to the inlet of the pump to hydraulically balance the thrust, on opposite ends, on the motor housing, and a second pump component carried by said wall and operatively associated by the mentioned fixed component, the fixed pump component comprising an annular sleeve having an internal diameter D and provided with radial and inwardly directed vanes on circumferential spacing B and having a width A, the rotational pump component comprising a ring having an external diameter D and a length C, said diameters, vane spacing, vane width and ring length being proportionally related substantially as follows:

-Jll to 1.0 %=O.25 130 0.5

and the pitch of the propellers being the range between eight (8) and twenty-two (22) per circumference, and

P .4" D2 89 to 2 a said proportionally related internal and external diameters, circumferential spacing, vane width, and ring length providing a pump having a shut-01f brake horsepower lower than the peak horsepower of the pump.

14. In a pump, a fixed tubular housing, a pump component fixedly carried within the housing, a pair of oppositely arranged coaxial and hollow caps within said housing, one at the inlet and the other at the outlet end of the pump, with an annular passage therebetween, a fixed axle carried by one cap and extending coaxially toward the other cap, a motor stator between the caps and fixed on the axle, an enclosed motor housing rotationally mounted on the axle and enclosing the motor stator, said motor housing having an outer tubula' wall, a motor rotor carried by said wall in electrical association with the stator, a second pump component carried by said wall and operatively associated by the mentioned fixed component, an opening in the cap at the inlet end of the pump to admit inlet pressure to the interior of said cap, means to conduct such inlet pressure around the motor housing and into the interior of the other cap, the pressures in said cap interiors being equal and opposite and thereby hydraulically balancing the thrust, from opposite ends, on the motor housing.

15. In a pump, a fixed tubular housing, a pump component fixedly carried within the housing, a pair of oppositely arranged coaxial and hollow caps within said housing, one at the inlet and the other at the outlet end of the pump, with an annular passage therebetween, a fixed axle carried by one cap and extending coaxially toward the other cap, a motor stator between the caps and fixed on the axle, an enclosed motor housing rotationally mounted on the axle and enclosing the motor stator, said motor housing having an outer tubular wall, a motor rotor carried by said wall in electrical association with the stator, a second pump component carried by said well and operatively associated by the mentioned fixed component, an opening in the cap at the inletend or" the pump to admit inlet pressure to the interior of said cap, means to conduct such inlet pressure around the motor housing and into the interior of the other cap, the pr ssures in said cap interiors being equal and opposite and thereby hydraulically balancing the thrust, from opposite ends, on the motor housing the fixedly carried pump component comprising a multi-stage unit having at least two side-by-side interiorly-open bowl units and an enclosure for said units having a circumferential wall, said unit being interposed between the inlet and outlet ends of said housing and fixedly connecting a said ends, and the second pump component comprising a multi-stage set of impellers in operative association with the mentioned bowls.

16. A pump comprising a tubular housing provided with two fixed longitudinally spaced hollow caps, one at the inlet and the other at the outlet end of the housing, a motor stator carried by one cap and disposed in the space therebetween, a motor rotor around the stator and having ends closing the hollows of the caps, the inlet and outlet of the pump being connected by a tubular passage defined between the housing on the outside and the caps and motor rotor on the inside, cooperating pump components extending into said passage from said housing and motor rotor, an opening in the cap at the inlet end of the pump to admit inlet pressure to the interior of said cap, means to conduct such inlet pressure around the motor housing and into the interior of the other cap, the pressures in said cap interiors being equal and opposite and thereby hydraulically balancing the thrust, from opposite ends, on the motor housing.

White June 14, 1927 I-larlamofi Sept. 3, 1946 

1. A PUMP COMPRISING A FIXED TUBULAR HOUSING, TWO HOLLOW, LONGITUDINALLY SPACED END CAPS WITHIN AND RIGIDLY CONNECTED TO SAID HOUSING, ONE AT THE INLET AND THE OTHER AT THE OUTLET END OF THE PUMP, A FIXED AXLE EXTENDING FROM ONE CAP TOWARD THE OTHER, AN INDUCTION MOTOR STATOR FIXEDLY CARRIED BY SAID AXLE BETWEEN SAID CAPS, A TUBULAR WALL COAXIAL WITH AXLE AND DISPOSED BETWEEN SAID CAPS, A PAIR OF CAP PLATES ON OPPOSITE SIDES OF THE STATOR CLOSING THE ENDS OF SAID TUBULAR WALL AND RESPECTIVELY CLOSING THE HOLLOWS OF THE CAPS A ROTATIONAL BEARING BETWEEN ONE CAP AND THE CAP PLATE AT THAT END, AN ANTIFRICTION BEARING BETWEEN THE LATTER CAP PLATE AND THE AXLE, AN ANTI-FRICTION BEARING BETWEEN THE OTHER CAP PLATE AND THE AXLE, MEANS RIGIDLY CONNECTING SAID TUBULAR WALL AND THE CAP PLATES TO FORM A STATOR-ENCLOSING ASSEMBLY ROTATIONAL ON THE AXLE AND HAVING AN INTERIOR SPACE, A MOTOR ROTOR CARRIED BY SAID TUBULAR WALL IN ELECTRICAL RELATIONSHIP TO THE MENTIONED STATOR, AN ANNULAR PASSAGE BEING DEFINED BETWEEN THE TUBULAR HOUSING AND THE TUBULAR WALL, AND COOPERATING PUMP COMPONENTS DISPOSED IN SAID PASSAGE, ONE CARRIED BY THE ROTATIONAL TUBULAR WALL AND THE OTHER BY THE FIXED TUBULAR PUMP HOUSING, THE HOLLOWS OF BOTH CAPS BEING VENTED TO THE INLET END OF THE PUMP TO PROVIDE EQUAL AND OPPOSITE PRESSURE IN SAID HOLLOWS AGAINST THE CAP CLOSURE PLATES TO BALANCE THE PRESSURE DIFFERENTIAL BETWEEN THE DISCHARGE AND SUCTION ENDS OF THE PUMP AS IMPOSED ON THE MOTOR ROTOR. 